I still don't get why the backslash is on keyboards to begin with. I don't think I've ever seen anyone write a slash backward with a pen. And even if folks do, you could've had only one slash anyways. Like, people are going to understand what it means, whether it's / or \.
I guess, it not being used for much else, does at least make it useful for escaping stuff and for Windows to use as path separator.